Marchesi was born in Milan, Italy. His parents ran a hotel and restaurant "L'Albergo del Mercato" in Via Bezzecca. It was here that he had his first experiences in the kitchen.

Two of his relatives, Luigi Ghisoni, who had been a chef at the Ritz, Madeira before he joined Marchesi's father running the business, and Domenico Bergamaschi, chef at Albergo del Mercato, were major influences on Gualtiero. He identified their ability to prepare traditional recipes perfectly, but also their talent of enhancing the flavour of simple ingredients.

At 17 he left school to work at the Hotel Kulm in St. Moritz. He then studied at a hotel school in Lucerne before returning to work at Albergo del Mercato. There he prepared traditional recipes for lunch but in the evening was given a free hand to experiment. He built a following for his avant-garde cuisine.

Gualtiero is an accomplished musician and follower of music. Through this he met his wife, a piano soloist and daughter of a famous soprano.

Gualtiero then worked at the "Ledoyen" in Paris, "Le Chapeau Rouge" in Dijon and "Troigros" in Roanne. On his return to Milan, he opened a small hotel with his parents, which he ran until 1977.

He then opened his first restaurant on Via Bonvesin de la Riva in Milan. Within a year he earned his first Michelin star, with another following the next year. It took another seven years, but then he eventually won the distinction of a third Michelin star – the first chef in Italy to do so.

In September 1993, Marchesi moved out of Milan to Franciacorta, between Bergamo and Brescia. He opened the Ristorante di Erbusco in the Albereta Hotel where his vision of global cuisine took root and flourished.

His restaurant Gualtiero Marchesi di San Pietro all'Orto in Milan, opened in 1998 and is a mix of traditional cooking and modern technology. It is also a cooking academy.

He opened a restaurant in Paris in 2001. In January 2001, he opened Ostaria dell’Orso, the oldest restaurant in Rome, located in a palace dating back to 1400 AD.

In 2011, Marchesi became the first celebrity chef to design two hamburgers and a dessert for McDonald's.[1]

In 2014 Gualtiero Marchesi took part in documentary film "29200 Puthod, l'altra verità della realtà" directed by Federico Angi biography of Dolores Puthod international painter.

The Laurea Honoris Causa in Food Science from the Universitas Sancti Cyrilli in Rome[citation needed]

Grand Prix ‘Memoire et Gratitude’, awarded by the International Academy of Gatronomy.

He was one of the founders of Euro-Toques, an association of some 3000 of the world’s most important chefs, and was its international president (2000–2002).

As the University Rector of ALMA, which offers the first International master's degree in Italian cuisine, Marchesi hopes to improve Italian catering and restaurant management.[2]

In June 2008, Marchesi denounced the scoring system of Michelin, and "returned" the stars, challenging the voting system of the guide, and claiming to only want to receive comments and ratings. As a result, the 2009 edition, "disappears" the Marchesi restaurant, being cited as the restaurant in which, without any of the comments taken from Marquesas.

"What makes me indignant is that we Italians are still so naive as to entrust the success of our restaurants – despite the great strides that the industry has made – to a French guide, that last year, as usual, assigned the highest score to just 5 Italian restaurants, compared to 26 French. If this isn't a scandal, what is it? [...] When, in June, I became polemical with Michelin I did it to set an example, to alert young people to help them understand that the passion for cooking cannot be subject to a vote. I know for certain, however, that many of them sacrifice themselves and work themselves to exhaustion in order to gain a Michelin star. It is neither healthy nor fair."

— Gualtiero Marchesi, November 2008

2012 Laurea Honoris Causa in Gastronomy Science from the Universitas of Parma